Which class should you use?

You are developing an application that will process personnel records.
The application must encrypt highly sensitive data.
You need to ensure that the application uses the strongest available encryption.
Which class should you use?

A.
System.Security.Cryptography.DES

B.
System.Security.Cryptography.Aes

C.
System.Security.Cryptography.TripleDES

D.
System.Security.Cryptography.RC2